Organopolysiloxanes prepared by the reaction of salts of silanols with halosilanes



Patented Sept. 4, 1951 ORGANOPOLYYSILOXANES PREPARED BY THE REACTION OF SALTS F SILANOLS WITH HALOSILANES James Franklin Hyde, CorningN. Y.,- assignor to ration of New York Corning Glass Works, Corning, N. Y., a corpo- No Drawing. Application July 12, 1947, Serial No. 760,710

The present invention relates to improved methods for the production of organosiloxanes.

This application is in part a continuation of my copending application Serial No. 628,965, filed November 15, 1945, and my copending applications with Oscar K. J ohannson, Serial No. 712,040, now U. S. Patent 2,472,799, and Serial No. 721,460 now U. S. Patent 2,438,055, filed'November 25, 1946, and January 10, 1947, respectively.

The properties of copolymeric organosiloxanes, such as resistance to decomposition and small change in physical properties at elevated temperatures, hydrophobic character, high dielectric capacity, and chemical inertness, suggest many uses for these compositions. The organosiloxane copolymers are of utility as lubricants, dielectric fluids, synthetic resins, paint and varnish vehicles, heat transfer media, hydrophobic agents for fabrics and ceramics, hydraulic fluids, and intermediatesin the production of siloxane elastomers.

Formerly, the organosiloxanecopolymers which contain mono--, di-, or tri-organo substituted siloxane structural units have been prepared by several methods. In generaL such copolymers have been prepared by the hydrolysis and cocondensation of silanes containing the desired organic groups attached tosilicon atomsthrough carbon to silicon bonds. The remaining valence bonds of the silicon atom of the silanes may be satisfied with readily hydrolyzable groups, such as halogen atoms or alkoxy radicals. The hydrolysis may be effected by reacting. a mixture of silanes with water. Frequently, during the hydrolysis of a mixture of organosilicon halides, a portion of the hydrolyzate separates irom the hydrolysis mixture as insoluble solid matter which has not entered into the copolymer. The hydrolyzate may contain residual hydroxyl groups which may be removed by condensation of thehldlolyzate as by heating. The physical properties of the organosiloxane copolymers are largely dependent upon the siloxane units. present, in the polymer, the proportions in which such structural units are present, and the extent of bodying of the hydrolyzate.

Objects of the present invention are toprovide improved methods for the production of organosiloxanes of definite structure,to provide improved methods for. the production of organosilcxane copolymers which contain a controlled amount of hydroxyl groups, and to provide improved methods for the production of completely condensed organosiloxane copolymers.

Other objects and advantages of the present 8 Claims. (01. 260-448.2)

invention will be evident from the following description.

In a preferred form of the present invention, org'anosiloxanes are prepared by the reaction of an alkali metal salt of an organo silanol with a silicon halide. The siloxanes so produced may be recovered from the reaction mixture.

The alkali metal salts of the organo silanols are organosilicon compositions in which an alkali metal is substituted for the hydrogen in one or more hydroxyls of a silanol which contains at least one silicon atom bonded to one or more organic radicals by carbon to silicon bonds, the silicon also being bonded to one or more of .the indicated hydroxyls. The alkali metal salts may contain one, two, or three organic groups attached to the silicon atoms of the silanol by carbon to silicon bonds. The hydrocarbon radicals of the alkali metal salts may be alkyl radical-s such as methyl, ethyl, propyl and higher; aryl, aralkyl, or alkaryl radicals such as phenyl, benzyl, or tolyl; or any combination of alkyl, aryl, aralkyl, or alkaryl radicals.

The alkali metal salts of the mono-organo silanols areorgan'osiloxanes in which the structure is dependent upon'the molar ratio of alkali metal to silicon. The mono-organo silicon salts have been prepared which have one, two, and three alkali metal atoms per silicon. These appear .to be compounds which correspond to the following typ'e'formulaez in which R represents a hydrocarbon radical, as above defined, M represents an alkali metal, and n isa-whole number. I I

The alkali metal salts of the diorgano silanols are organosiloxanes of the general type formula M0(R2SiO)nM, in which R represents a hydrocarbon radical as above defined, M represents an alkali metal, and n represents a whole number. The molar ratio of alkali-'metal'to silicon in the siloxane largely determines-the value of n.

The alkali metal salts of the triorg-ano silanols are organosilanes which correspond to the type formula RsSiOM, in which R represents a hydrocarbon radical as above defined, and M represents an alkali metal. The molar ratio of alkali metal to silicon is one in' the, tri-organo salts. These salts are assumed to be similar in structure to the mono-silanes.

The alkali metal salts of the organosilanols may form crystalline complex compounds which contain water of crystallization. Each salt is capable of forming a series of crystalline hydrates which contain varyingamounts of Water of crystallization. The amount of water which may be held in the crystal structure varies but in general those hydrates which contain less invention are compounds which contain at least one halogen atom attached to a silicon atom. The remaining valences of the silicon atoms may be satisfied with halogen atoms, organic radicals, or siloxy radicals. SiX4, RSiXs, R2SiX2, RaSiX, and X(RzSiO)'nR2SiX, where R. represents a hydrocarbon radical as above defined and X rep- 7 resents a halogen atom, are illustrative of suitthan about 3 mols of water per equivalent of alkali metal are stable, crystalline compounds. The alkali metal salts may, under certain conditions, form crystalline complexes with an alcohol or an alkali metal hydroxide.

The alkali metal salts of the organosilanols may be prepared by the reaction of alkoxy silanes containing the desired hydrocarbon radicals, the corresponding silanols, hydrolysis products of organosilanes which contain the desired organic groups and readily hydrolyzable groups such as alkoxy radicals or halogen atoms. or condensed siloxanes which contain the desired organic groups with an alkali metal oxide in the presence of water. The alkali metal oxide and water may be added to the reaction mixture as the alkali metal hydroxide or as an aqueous solution of the hydroxide. In order to eifect more intimate contact between the reactants, a lower aliphatic alcohol of boiling point below that of water may be added to the reaction mixture. By the elimination of water from the system, crystalline hydrates of the desired alkali metal salts are obtained.

The hydrated salts thus obtained may be dehydrated by subjecting the hydrates to a. high vacuum in the presence of a dehydrating agent. By selective dehydration, salts containing various amounts of water of crystallization may be 1 obtained. Anhydrous salts may also be prepared by the addition to the reaction mixture of a solvent of boiling point greater than that of water. After the removal of the water and alcohol-from the reaction mixture by boiling, the desired anhydrous salt may be obtained from solution in the solvent. Pyridine and toluene are examples of suitable higher boiling solvents.

The anhydrous alkali metal salts may be prepared by the reaction of alkoxy silanes containing the desired organic radicals, or products such as may be produced by the hydrolysis and condensation thereof, with alkali metal oxides under substantially anhydrous conditions. A lower aliphatic alcohol may be added to the reaction mixture to increase the rate of reaction either alone or in addition to other organic solvents.

The specific alkali metal salt formed may be controlled to some extent by the alkali metal to silicon ratio in the reaction mixture as well as by the organosilicon material in the reaction mixture. For example, the salts (RSiOOM)n, [RSi(OM)2]2O, RSi OM 3 may be prepared by the use of difierent proportions of the same reagents. Also the .value of n in the salt may be varied by variation of the ratio in which the reactants are employed. I

The silicon halides employed. in the present tion proceeds to completion.

able silicon halides.

It has been found that the alkali metal salts and the silicon halides enter into metathetic reactions. The principal products of such reaction 1 are the siloxane, in which the silicon of the salt is attached to the silicon of the halide by an oxygen atom, and the alkali metal halide. The alkali metal halides are insoluble in the siloxanes and in organic solvents. Thus, by removal of one of the products as an insoluble material, the reac- Siloxanes, which contain more than one type of siloxane structural unit, may be produced by the reaction of the alkali metal salts with mixtures of silicon halides or by the reaction of a mixture of alkali metal salts with a silicon halide.

siloxanes may be produced by the reaction of the hydrates of the alkali metal salts and the silicon halides. However better yields and more consistent results are obtained if the reaction mixture is maintained substantially anhydrous. The silicon fluorides are more stable with respect to water. The silicon fluorides may be reacted with the salt hydrates.

It is preferred that at least one of the reactants be present as a liquid phase. The silicon halides, at atmospheric pressure and room temperatures, are generally liquids. Reaction occurs on the addition of one of the reactants to the other. If desired, a solvent such as diethyl ether, dioxane, petroleum ether, toluene, benzene,

or pyridine may be added to the reaction mixture. By the use of such a solvent more intimate contact between the reactants is obtained, and the rate of reaction is increased. The solvent may be introduced into the reaction mixture as a solvent for either or both of the reactants, or it may be added to a mixture of the reactants.

The reaction between the alkali metal salts of organo silanols and the silicon halides may take place under widely Varied conditions. The rate of reaction may be increased by heating, or decreased by cooling the reaction mixture. The order of addition of the reactants may be varied. Reaction takes place upon the addition of either of the reactants to the other. However, in certain reactions the yield of any particular siloxane may depend to some extent upon the order of addition of thereactan'ts. Thus, in some reac tions it is desirable to add the silanol salt to the silicon halide, while in other reactions it is desirable to reverse the order of addition.

Several types of siloxanes may be produced by the reaction of the alkali metal salts of the 'organosilanols withthe silicon halides. The type of siloxane produced is dependent upon the ratio in which the reactants are present in the reaction mixture, as well as upon the specific reactants employed.

Completely condensed siloxanes may-be prepared by the reaction of an alkali metal "salt of an organo silanol with an equivalent amount-of a silicon halide. 'The siloxanes thus produced contain no residual groups hydrolyzable upon contacting the siloxanes with water. For example, alkali metal salts of triorgano silanols may be reacted with organosilicon halides to produce al nde d fin M en n s an a l ta and .X repres nt a a og a om The following illustrate types of reactions which are obtained with salts ofv diorganosilanols and partially condensed derivatives thereof:

The salts of Equations 6 and 7 may likewise be reacted with silicon tetrahalide or mono or diorgano silicon halides with the production of ecmnl tel con n e 11 5- Lilgewise with respect to the three types of mono-organo substituted silicon salts above referred to, simple compounds; are obtainable by reacting theIn with a triorganosilicon halide, whereas completely condensed complex siloxanes are obtainedwhen they are reacted with the silicon halides of lower-degree of organic substitution.

SHOE-n95 capab of her de s tio may also. b re ar d b t e rea t o o a alkali metal salt with a silicon halide by having one of the reactants in ex'cessin the reaction mixture. The use of an excess of either the alkali metal seat the halide-result i e o ties. at qpn l me rs whic p n hydrol si are 9?:98916- 9 l! 1 9QQQQQ 3. n??- u of an esc ssor' nrcon. halidein t reaction mix e e'a. silcxane ma be rod edwhieh conta ns halogen radicals attached to silicon atoms. The

halogen 'substituents may be removed-by washing the siloxane with an excess of water} Following the washing the siloxane contains "resid-' ual hydroxyl groups which may be removed by bodying or condensing the siloxane. The amount of residual hydroxyl groups in the washed siloxanes is dependent upon the; amount of excess silicon chlorides in the reaction mixture. In this manner the extent of condensation of the siloxanes may be controlled.

Gopolymers consisting of more than two organosiloxane structural units may be prepared by the use of the method as herein described. A mixture of silicon halides maybe reacted with an alkali metal salt of an organosilanol, or a mixture of salts may be reacted with v a silicon halide. The extent of condensation of the siloxane copolymer produced may be controlled by the ratio of total halide to' total alkali metal in the reaction mixture.

The composition of the copolymers produced by the methods as herein 'descr'ibedis not entirely determined by the random distribution of the siloxane structural unitsthroughout the copolymer structure. Thus co-polymers of definite composition and molecular size "may be prepared in excellent yield by the-methods of the present invention. Also, certain disadvantages of the hydrolysis procedure,- such as the formation'of insoluble matter during the hydrolysis of a mixture of silanes. are eliminated by the methods of the present invention.

The following examples illustrate specific modes of employing the process of the present invention: I Y

' Example 1 [CH3SiOONa]n was prepared by reacting a 50 per cent by weight aqueous. solution of NaOH with a monomethyl siloxane hydrolyzate in equal molecular amounts. Ethyl alcohol was. added in amount to give a single phase reaction mixture. Upon removal of solvent and water by distillation, a white crystalline powder was obtained. The powder was dehydrated by heating at a temperature of C. over phosphorous pentoxide until a constant weight was obtained. The neutraliz'ation equivalent of the salt thus obtained was 102.4. The calculated neutralization equivalent of anhydrous [CHzSiOONah is 98.

A copolymer consisting of monomethyl siloxane structural units and trimethyl siloxane structural units was prepared as follows:

The above salt was added to a 54 per centby weight solution of (CH3)3SiCl in a mixed solvent composed of 8.5 per cent by weight anhydrous pyridine and 91.5 per cent by weight anhydrous diethyl etherin a reaction vessel in amount to give a sodium to chlorine atomic ratio of 3 to 5. NaCl precipitated from the reactionmixture and was removed by filtration. The solvent and excess (CHa)3SiC1 were removed from the filtrate by distillation. A copolymer of 473 centistokes viscosity was obtained. The copolymer was distilled at 15 mm. pressure. 86 per cent of the copolymer was non-volatile at 355 C., and 15 mm. pressure. The viscosity of the residue was 830 cs- 8 s Example 2 I CBHSSiOONSm containing 0.5 mol of water of hydration per sodium atom was prepared by the reaction of monophenyl siloxane hydrolyzate with sodium hydroxide. Saturated aqueous sodium hydroxide was added with stirring to a 41.1% solution by weight of C6H5Si01-5 in a mixed solsalt obtained on removal of solvent was dissolved in a solvent composed of 47.5 per cent by weight toluene, 50.7 per cent by weight ethanol, and 1.8 per cent by weight water. The salt was dissolved in the solvent at the boiling point. Upon cooling, crystals were obtained which had aneutralization equivalent 214.5. The salt was dehydrated at 170 C. over phosphorous pentoxide until a constant weight was obtained. The neutralization equivalent was then 168. The calculated neutralization equivalent of the. anhydrous salt is 160. This indicates the salt is the compound [CsHsSiOONah containing 0.5 mol of wa; ter of hydration per equivalent ofv sodium. A copolymer of mono-phenylsiloxane units and trimethyl siloxane units was prepared as follows: a

The above salt was added with stirring to a 16.5 per cent by weight solution of (CH3)aSiC1 in a mixed solvent composed of 35.5 per cent by weight diethylether and 64.5 per cent by weight toluene in amount to give a sodium to chlorine atomic ratio of 2 to 3. .The reaction was complete after hours. The sodium chloride which had precipitated during the reaction was removed by filtration after 16 hours. The residuewas extracted with diethyl ether. The solvent and excess (CH3)3SiC1 were removed from theether extract by distillation. An 85 per cent yieldof an oil of 116,500 0. s. viscosity was obtained.

Example 3 v A copolymer comprised of monophenyl siloxane units and dimethylsiloxane units was prepared as follows:

The salt described in Example 2 was added with stirring to a 6 per cent by weight solution to (CH3)2SiC12 in diethyl ether in amount to give a sodium to chlorine atomic ratio of 1. NaCl precipitated immediately from the reaction mixture and was removed by filtration." The solvent was removed from the filtrate by distillation under reduced pressure. A hard brittle resin was thus obtained. The resin did not melt on heat ing to 300 C. but'passecl through a rubbery stage and a punky gel state as the temperature was increased, and reverted to its original state upon cooling.

' Example 4 I (CcHs) (CzHs) Si ('OC2H5)2 Was added with stirring to suiiicient water to hydrolyzethe 'silane to the siloxane. An amount of NaQH was present in the hydrolysis nenstrum to give-a silic on to sodium ratio of 3. The water and ethyl alcohol in the reaction mixture was removed by distillation at reducedpressure. A clear, viscous fluid was obtained which contained NaO [(CsHs) (Cal-I5) SiOJnNa by weight solution of the above salt in benzene in amount to give a chlorine to sodium ratioof 1.

NaCl precipitated from the reaction mixture ime. mediately. After a period of 2 hours the reaction mixture was diluted with diethyl ether and washed with dilute aqueous HCl and water. INaCl was removed by this wash. The solvent and water were removed by distillation under reduced pressure. A clear, water white liquid remained. The absence of free silicic acid indicated complete copolymerization.

A portion of the copolymer was maintained at a temperature of 250 C. for 108 hours without gelation. At the end of this period the copolymer was viscous and tacky at 25 C., but still quite fluid at 250 C. Another portion of the copolymer was air-blown at a temperature of 220 C. for 72 hours to give a high viscosity resin. A 70 per cent solution of this resin was applied to a, cadmium coated copper strip. The coated metal was heated forone hour at 150" C., and for 8 hours at 250 C. The coating was tack-free. The coating was unaffected by heating for hours at 250 C.. and could be bent over a 0.125 inch mandrel without cracking the coating.

Example 5 NaO[ (CsHs) (C2H5)rSi'O]nNa, where n has an average value of 4, was prepared by reacting a 50 per cent solution of aqueous NaOH witha phenyl ethyl siloxane hydrolyzate in amountto give a silicon to sodium ratio of 2 to 1. Sufficient toluene was added to obtain a homogeneous reaction mixture. The reaction mixture was heated to remove water by distillation. Thus a substantially anhydrous toluene solution of NaO[ (CsHs) (can) SiOJnNa where n has an average value of 4, was obtained.

A copolymer consisting of phenyl ethyl siloxane structural units and siloxane structural units containing no organic substituents was prepared as follows:

A 50 per cent by weight solution of the above salt in toluene was added gradually to a 20 per cent by weight solution of vSiCh in toluene in amount to give chlorine to sodium ratios of 1, 2, and 3 respectively. In each case a precipitat of N aCl formed immediately. The reaction mixtures were stirred until .reaction was complete and refiuxed for a short time to insure complete reaction. The reaction mixtures were washedwith water, until neutral. The NaCl was removed by this wash. Th results obtained from the copolymerization are summarized in the following table: v

' wti'tts's Vise. S1O2% Cl/Na Yield 1 OH Found 3 Hrs.

(C. s.) i I C816. I .I 12500 C a Per cenz Per cent 7 Per cent 1 97.2 0.99 2,056 42.5 42.39 36.4 2 100.5 2.7 (X259 44;8 44.08 22.7 3 100.3 2.3 10,000 141.3 44.95 2 Z.3

'lheoreticalyield calculated on anhydrous basis.

reaction mixture were removed by distillation under reduced pressure to give a clear, extremely viscous mass containing N'aO[ (Cs-H) (C'zI-Is) S] nNa where n has an average value of 10.

A copolymer consisting of phenyl ethyl siloxane structural units and siloxane structural units containing no organic substituents was prepared as follows:

A 2'7 per cent by weight solution of this salt in benzene was added with stirring to a 'l per cent by weight solution of S1014 in benzene in amount to give a chlorine to sodium ratio of 4. NaCl precipitated immediately. The reaction mixture was stirred for hours. The reaction mixture was then diluted with a volume of ether equal to one-half the volume of the reaction mixture. This solution was washed with water to remove the NaCl and to hydrolyze residual chlorine. An oil of 3,333 c. s. viscosity remained on evaporation of solvent and water. After standing 120 hours the viscosity of the oil increased to 6,500 c. s. The viscosity was 3,334 c. s. after heating'at 400 C. for 1 hour. The heating may have caused bond rearrangement with the formation of cyclic siloxanes. Air blowing at 220 C. increased the viscosity of the 6,500 c. s. material but did not cause gelation.

Example 7 A copolymer consisting of phenyl ethyl siloxane structural units and phenyl siloxane structural units was prepared as follows:

A 31 per cent by weight solution of the sodium salt described in Example 6, in benzene was added gradually with stirring to a 1'7 per cent by weight solution of phenyl silicon trichloride in benzene in amount to give a chlorine to sodium ratio of 3. NaCl precipitated from the reaction mixture immediately. The NaCl was filtered from the reaction mixture. The solvent was removed by distillation at reduced pressure. The residue was washed with water until neutral. A liquid of 3,720 c. c. viscosity at C. remained. After heating at 250 C. for 24 hours, the viscosity of the liquid increased greatly. The heat-bodied resin was applied to a cadmium-coated copper plate and heated 44 hours at 250 C. A tough, leather-like coating was obtained. The resin also may be bodied by airblowing at elevated temperatures.

Example 8 Powdered KOH (neutralization equivalent: 61.6) was added with stirring to a 33.3 per. cent by weight solution of [(CH3)2S1O]3 in toluene in amount to give a silicon to potassium ratio of 117. The viscosity of the reaction mixture became constant at 25.32 centistokes after a total of 144 hours at 100 C. Metallic potassium was added to the reaction mixture in amount sufficient to react with the water present due to the use of powdered KOH. After the addition of the metallic potassium, the silicon to potassium ratio was 58.5. Thus, a toluene solution of anhydrous KO [(CHs) 2SiOlnK was prepared in which 11. has an average value of 117. The viscosity of the salt solution was 16.08 c. s. after heating at 100 C. for 24 hours.

A high molecular weight copolymer consisting of dimethyl siloxane structural units was prepared as follows:

(CH3)2SiC12 in toluene solution was added to the salt in amount calculated to give a chlorine to sodium ratio of 1 NaCl precipitated on the ad- 10 dition of the (CH3)2SiC12. After 48 hours at 100 C. the viscosity of the reaction mixtures had risen to 24.70 c. 5., although the reaction mixture was alkaline.

A 1 per cent solution of (CH3) 2SiC12 in toluene was added in amount suflicient to neutralize the reaction mixture. After 72 hours at 100 C. the viscosity of the neutral solution increased to 43.47

(Cal-I5) 2Si(ONa) 2 was prepared by the reaction of NazO was added with stirring to a 13.8 per cent by weight solution of [(CsI-Is) 2SiOl4 in toluene in amount to give a silicon to sodium ratio of 0.5. Suflicient methanol was added to the reaction mixture to disperse the NazO. The reaction was complete in two hours. The solvent was removed by distillation at reduced pressure. A white powder remained after removal of the solvent. The powder was dehydrated by heating over phosphorus pentoxide at a temperature of 100 C. for 24 hours, and at 1'70 C. for 48 hours. The neutral equivalent of i the product was 135. The calculated neutral equivalent for anhydrous (CsI-I5)2Si(ONa)2 is 130.

A copolymer. consisting 'of diphenyl and dimethyl siloxane structural units'was prepared by adding this salt with stirring to a 19.6 per cent anhydrous pyridine solution of (CH3)2S1C12 in a reaction vessel in amount to give a chlorine to sodium atomic ratio of 1.5. A precipitate of NaCl formed immediately in the reaction mixture. After 1 hour a volume of pyridine equal to one-half the volume of the original solution was added to the reaction mixture. After 16-18 hours an equal volume of 28.5 per cent solution of water in pyridine was slowly added to the reaction mixture. The precipitated NaCl was removed by filtration, and the filtrate was washed with water until neutral. Upon removal of the salt an yield of a 3,835 c. s. oil was obtained. The oil contained 1.29 per cent by weight hydroxyl groups. A portion of the oil was treated with 0.4 per cent by weight of a 50 per cent aqueous solution of KOH at a temperature of C. In less than one hour the copolymer was com verted into a tacky, infusible gel.

Example 10 KO[(CH3)2SiOlnK in which n has an average value of 382, was prepared by the addition of powdered KOH with stirring to [(CH3)2SiOl3 in a reaction vessel in amount to give a Silicon to potassium ratio of 191. The reaction mixture was maintained at a temperature of 77 C. during the addition.

A copolymer consisting of dimethyl siloxane and trimethyl siloxane structural units was prepared by adding trimethyl silicon monochloride, in diethyl ether solution to portions of the salt heated for varying times'at 77 C. in amount to give a chlorine to potassium ratio of 1. Potassium chloride precipitated from the copolymer 1 solution. The K01 was removed by filtration and the etherwas removed by distillation at atmospheric pressure. The copolymers were heated at 110 C. under reduced pressure for a period of 2 hours, cooled, and weighed. The percentage of high polymer siloxane salt present was calculated from the ratio of weight of the copolymer to the initial weight of the respective portion. The error introduced in the calculations due to the replacement of potassium (atomic weight 29.1) by a (CHzOaSigroup (equivalent weight 73) is slight. Thus, in the salt KO[(CH3)2S10]382K, this error is 0.24 per cent.

The following table illustrates the relation of heating. time to polymerization:

Heating High Poly- Timo mer Silox- (77 C.) ane Salt Minutes Per cent Example 11 (CH3)3S1OK was prepared by the reaction of KOH with hexamethyldisiloxane. KOH containing- 16.7% water was added to.[(CHa) 3Si]2O in a reaction vessel in amount to give a sodium to silicon atomic ratio of 1. Suflicient methanol to disperse the alkali was added to the reaction mixture. The reaction mixture was allowed to stand at room temperature for 12 hours. .It was then heated to a temperature just below boiling for 24 hours. The reaction mixture was refluxed and the weight loss of the reaction mixture was made up by the addition of hexamethyldisiloxane. The reaction mixture was extracted with diethyl etherin a Soxhlet extractor. The ether extract was evaporated to dryness and placed under a high vacuum.

A copolymer consisting of dimethyl siloxane and.- trimethyl siloxane, structural units was prepared by adding this salt with stirring .to [(CH3) 231014 at a temperature of 77 C. in amount to give a silicon to. potassium ratio -of 190. The reaction vessel was maintained at 77 C. for 20 hours, The reaction mixture was cooled, weighed, andan equal amount by weight of a 2 per cent solution of (CHalsSiCl in diethyl ether wasadded. The solvent was removed by distillation and the mixture was maintained .at a temperature of 95 C. for 3 to 4 hours at a pressure of 15 mm. to remove the unreacted Example 12 KO[(CH3)2SlO]nK ln which n has an average value of 400, was prepared by the addition of .powdered KOH with stirrin to [(CH3)2SiO]5 in a reaction vessel in amount to give a silicon to potassium average ratio of 200. The reaction se so 0.

mixture was maintained at a temperature of 120 C. A copolymer consisting of dimethyl siloxane and trimethyl siloxane structural units was prepared as follows:

The salt prepared as above was maintained at a temperature of 120 C. Portions of the salt were removed at 5-minute intervals, cooled, and weighed. Trimethyl silicon monochloride. in diethyl ether solution was added to the weighed portion of the salt in amount to give a chlorine to potassium ratio of 1. Potassium chloride readily precipitated from the copolymer solution. The KCl was removed by filtration. The ether was removed from the solution by distillation at atmospheric pressure. The co:- polymer wa maintained at a temperature of C. at reduced pressure for a period of 2 hours, cooled, and weighed. The percentage of dimethyl siloxane polymerized to high boiling material by the treatment withv KOH at C. was calculated from the. ratio of weight of the copolymer to the initial weight of the respective portion.

The following table illustrates the relation of heating time to polymerization:

Heating Siloxane Time Polymer- (120 C.) ized Minutes Per cent By the addition of the (CI-193E101 to the salt, reaction occurred which eliminated KCl and introduced (CH3)3Si-units at the ends of th polymer molecules.

Example 13 NaO[(CeH5) (CH3) SiOJHNa in which n has an average value of 4, was prepared by the reaction of sodium oxide with the cyclic tetramer of phenyl methyl siloxane. Na2O was added with stirring to a 63 per cent solution of [(CsI-Is) (CI-Ia.) S1014 in petroleum ether, boiling range 30-60 C., to give a silicon to sodium ratio of two. 4.4 per cent by weight methanol was added to the reaction mixture. The reaction was complete after 8 hours reflux. Upon removal of the solventat reduced pressure, a thermoplastic solid material remained in the reaction vessel. After desiccation over phosphorous pentoxide, the neutralization'equivalent of the solid became constant at a value of 3-20. The neutralization equivalent indicates that the solid is a mixture of sodium salts of the type'NaO[(CaH5) (CI-Ia) SiOlnNa in which n has an average value of 4.

. A copolymer consisting of phenyl methyl siloxane and trimethyl siloxane structural units was prepared as follows:

183.7 grams of a 32 per cent solution of phenyl methyl siloxane sodium salt, as prepared above, in ether, boiling range 30-60 0., was added with stirring to '79 grams of a 19 per cent solution of (CH3)3SiCl' in petroleum ether, boiling range When the reaction was complete, the reaction mixture was washed with aqueous sodium bicarbonate solution, dilute aqueous 13' acetic acid solution, and water until neutral. The solvent was removed at reduced pressure, and. the .siloxane mixture was distilled. at armssure of 1mm. 7

A distillation analysis of the siloxane mixture gave the, following results:

141- tionof. (CHshSiCl in anhydrous pyridine, in amount to give a sodium to chlorine ratio of 1. The reaction mixture was cooled by indirect heat exchange with ice. After the reaction was complete, the reaction mixture was washed with per cent aqueous sodium bicarbonate solution and with water and crushed ice until neutral.

. Piessure Temp, vise, Per C t The siloxane products were removed from the re- I (O-SJ Yleld action mixture by the use of a separatory funnel. l The reaction mixture was dried with anhydrous 4 5 V potassium carbonate and filtered. I 511 31 Distillation analysis of the siloxane products gara zso-soo 118. 3 gave the following results:

ITO? 100'.) 2 Per Cent Pressure (mm) ig ff g gg The material of boiling point greater than salt used) 200 C. at a pressure of 1 mm. is of utility as a vacuum :difiusion pump fluid. under 103 2.3 103-101 75.0- Example 14 I v still 1101a up... 5.4

N320 WaS' added with stirring to a 60 percent T0181 3110x8119 llmducts -7 solution of [(0113) 251014 in pyridine in a reaction vessel in amount to give a silicon to sodium ratio of 2, whereby to produce the salt Na0 (CH3) 2SiO'] sNa reaction was complete in 15 hours. The reaction mixture was filtered and the residue dried under reduced pressure. The residue, containing the desired sodium salt, was dissolved in ace- D rm .naorrcrrmsionlva, prepared as above, was

added with stirring to (CH3)3SiCl, in'the form,

of an 8.5 per cent solution in toluene, in amount to give a sodium to chlorine ratio of 1. The reaction mixture was cooled with ice by indirect heat exchange. After the reaction was complete, thereaction mixture was washed with a 5 per cent aqueous sodium bicarbonate solution and with water and crushed ice until neutral. The reaction mixture was dried with anhydrous potassium carbonate and filtered. The toluene 'wasremoved by distillation at atmospheric pressure. The product was dissolved in diethyl ether,

'washed with water, and the ether was removed 'by distillation at atmospheric pressure. The siloxane mixture was distilled at reduced pressure and a 47.6 per cent by weight yield of the desired (CH3) 3Si0 [Si(CH3) 2--Q]3Si(CI-I3) 3 was obtained.

v Example 15 NaO[(CH3)2SiO]aNa, prepared as in Example l4, was'added with stirring to a 7.1 per cent solu- The siloxane of boiling range 103-107 c. was identified as (CH3) 3SiO [(c-Ho asioiasircrrai 3.

Example 16 NaOHCsHsJaSiOlzNa was prepared by the reaction of sodium oxide with octaphenylcyclotetrasil-oxane. NazO was added with stirring to a 16.5 per cent, by weight, solution of in toluene in amount to give a sodium to silicon atomic ratio of 1. Sufficient methanol was added to the reaction mixture to give a single phase system. The reaction mixture was warmed slightly andstirred for 15 to 16 hours. The solvent Was evaporated under reduced pressure.

The salt thus obtained was dissolved in a mixed solvent of methanol and toluene. The salt solution was left to stand at room temperature for about 129 hours. The salt was recrystallized by. partial evaporation of the solvent. The salt was then heated at l00 C. at 1 mm. pressure over anhydrous phosphorous pentoxide for 24 hours. The dehydrated salt had a neutralization equivalent of 227. The calculated neutralization equivalent for anhydrous NaOE (06115) zsiOlzNa A copolymer consisting of diphenyl siloxane structural units and monophenyl siloxane struc- 1 Example 1 7 NaO[(CsH5) (CH3) SiOlzNa was prepared by the reaction of sodium hydroxide with phenyl methyl siloxane hydrolyzate. (C'eHs) (CH3) SiO was added with stirring to a 19.5 per cent solution of NaOH in a. mixed solvent composed of 43.5 per cent water and 56.5 per cent ethanol in amount to give a silicon to sodium atomic ratio of 1.

a, The excess water and alcohol were removed at 15 room temperature under vacuum. The reaction mixture was dissolved in toluene and refluxed until all water had been removed from the system. The anhydrous salt is insoluble in toluene. The salt was removed from the toluene by distillation and was washed with petroleum ether,

boiling range 30 to 60 C. The salt was dried at 100 C. at 0.1 mm. pressure for 36 hours. An 89 per cent yield of NaO[(CeH5) (CH3)SiO]zNa was obtained. v

A copolymer consisting of phenyl methyl siloxane and phenyl dimethyl siloxane structural units was prepared by adding this salt with stirring to -(CsH5)(CH3)2SiCl in amount to give a chlorine to sodium atomic ratio of 1.065. After stirring 12 hours the reaction mixture was washed with 10 per cent aqueous sodium bicarbonate solution and with water until neutral. The siloxane layer was separated and dried over anhydrous potassium carbonate. volatile components were removed at room temperature under vacuum. An 85 per cent yield of based on sodium salt used, was obtained.

. Example 18 A copolymer consisting of phenyl methyl siloxane and diphenyl methyl siloxane structural units was prepared by adding the salt N-aO (CsH5) (CH3) SiOlzNa prepared as in Example 17 with stirring to a 22 per cent solution of (CsH5)2(CH3)SlC1 in a mixed solvent composed at 87 per cent pyridine and 13 per cent diethyl ether in amount to give a chlorine to sodium ratio of 1.065. After stirring 12 hours, the reaction mixture was washed with 10 per cent aqueous sodium bicarbonate solution andv with water until neutral. The siloxane layer was separated and dried over anhydrous potassium carbonate. The solvent and volatile components were removed at room temperature under vacuum. An 80 per cent yield of Si(CsHa)z(CHa) based on sodium salt used, was obtained.

Example 19 A copolymer consisting of phenyl methyl siloxane and phenyl siloxane structural units was prepared by adding the salt Na[ (Cal-I) CH3) SlO] 2N3.

plastic resin was obtained.

Example 20 NaOH was added to (CI-13 zSiOC2H5 in amount to give a sodium to silicon atomic ratio of 1. The reaction mixture was refluxed for 42 hours. Sufficient methanol was added to the reaction mixture to disperse the alkali. The al- The solvent and.

cohol and water were removed by distillation under vacuum. The residue was extractdfwith boiling petroleum ether of boilingrange -100?- C. The petroleum ether extract was evaporated to dryness and dehydrated by heating under vacuum. The salt was purified by sublimation at 130-140 C. under high vacuum. The neutral ization equivalent of the salt so obtained was 113. The calculated neutralization equivalent of the anhydrous salt is 112.

A copolymer consisting of trimethyl siloxane structural units and siloxane structural units containing no organic substituents was prepared by adding this salt as a 35.6 per cent solution in petroleum, boiling range 30-60" C. with'stirring to a 30.9 per cent solution of SiCh in petroleum ether, boiling range 30-60 'C;, to give a sodium to chlorine atomic ratio of l.= A precipitate of NaCl formed immediately. After '3 hours at 25 C., the NaCl was removed by filtration. The solvent was removed from the filtrate by distillation at reduced pressure." The residue from the filtrate was fraction-ally distilled at -12 mm. pressure. The expected compound Si[OSi(CH;)a]4

was obtained. I

Example 21 r tion of CHsSiCls in petroleum ether, boiling range 30-60" 0., in amount to give a chlorine to sodium atomic ratio of 1. The reaction vessel was cooled by indirect heat exchange with ice. The reaction mixture was washed with wateruntil neutral. The solvent was removed bydistillation at atmospheric pressure. The residue was fractionally distilled at 14 mm. pressure. The expected product, C1-1aSi[OS i(CI-Ia)slz wasobtained.

Example 22 der reduced pressure. CsH5Si[OSi(CH3)3]3, boiling point --110 C. at 13 mm., was separated and identified.

Example 23 A copolymer consisting of trimethyl and triphenyl siloxane structural units was prepared by adding (CHsMSiONa, prepared as in Example 20, as a 2.2 per cent solution in anhydrous diethyl ether with stirring to a 8.2 per cent solution of (CaHs) asiCl in anhydrous diethyl ether in amount to give a sodium to chlorine atomic ratio of 1. The reaction was complete in 20 hoursat room temperature. The precipitated sodium chloride, which was produced during the reaction, was removed by filtration. The solvent was removed from the filtrate at reduced pressure, and the residue was washed with ethanol. An

17 essentially quantitative yield of 1,1,1-trimethyl- 3,3,3-triplienyl disiloxane (melting point 47-49" C.) was obtained.

Example 24 obtained by the vacuum treatment was dissolved in a mixed solvent composed of equalvolumes of methanol and toluene. The toluene soluble portion of the residue was heated at 225 C. at a pressure of 0.1 mm. The viscous, partially crystalline mass remaining had a neutralization equivalentlof 181. The calculated neutralization equivalent of (Cal-I) (CH3)2SiONa is 174.

AI copolymer consisting of phenyl dimethyl siloxane and .trimethyl siloxane structural units was prepared by adding a 45' percent solution of (Cal-I5) (CH3)2SiONa, 'as above prepared; in diethyl ether with stirring to (CI-13):;SiCl in amount to give sodium to chlorine atomic ratio or 1. NaCl precipitated throughoutthe addition. The reaction was complete in 4 hours. The residue was distilled at reduced pressure. An essentially quantitative yield (C6115) (CH3) 2Si-O-Si(CH3) 3, which had a boiling point of 95-96 C. at 15 mm. pressure, was obtained.

Example 25 NazO containing a small amount of water was added to [(CeH5)2(CI-I3) S1120 in amount to give a sodium to silicon atomic ratio of 1. The reaction mixture was heated to a temperature of 140-150 C. Small amounts of methanol to aid in dispersing the alkali were added to the reaction mixture during the heating. Methanol and water were removed by heating under a vacuum.

The viscous product remaining after the vacuum treatment was extracted with boiling toluene. The toluene solution was evaporated, and the residue was dissolved in petroleum ether of boiling range 90-100 C. Upon the addition of petroleum ether of boiling range 30-60 C., the mono-hydrate of (Cel-I5)2(CI-I3)SiONa precipitated. The mono-hydrate was dehydrated by heating at 170-180 C. for 5 to 6 hours at a pressure of 5 to 18 mm. The neutralization equivalent of the salt so obtained was 238. The calculated neutralization equivalent of the anhydrous salt is 236.

A copolymer consisting of diphenyl methyl siloxane and triphenyl siloxane structural units was prepared by adding the salt (CsHs) 2 (CH3) SlONa acetate and 'againfrom petroleum ether, :boiling range 30 to 60 C. A per cent yield of I (CcHs) 2(CH3) Si-O-SflCsI-Ia) 3 melting point 74-.758" C. was obtained.

Iclai m:- y

. 1. The method of preparing organosiloxane materials-wvhich comprises reacting, an alkali metal salt of an organo silanol, in which the organic radicals are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon by carbon to silicon bonds, with a siliconhalidein which any organic radicals present thereinare monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon-by carbon -to;silicon,bonds, whereby a siloxane, is produced in'which the silicon of the silanolis linked to the silicon ofthe silicon halide through an oxygen atom. v 2. The. method of upreparing organosiloxane materials .which comprises reacting an alkali metal salt of. an organo silanol, in which the organic radicals are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon by carbon tov silicon bonds, with an organosilicon. halide inwhich all of the organic radicals are. monovalent hydrocarbon radicals free of aliphatic unsaturation, and arelinked to the silicon by. carbon to silicon bonds-whereby a siloxane is produced in which the silicon of the silanol is linked to the silicon of the silicon halide through an oxygen atom.

3. The method of preparing organosiloxane materials which comprises reacting an alkali metal salt of an organo silanol, in which the organic radicals are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon by carbon to silicon bonds, with a silicon halide in which any organic radicals present therein are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon by carbon to silicon bonds whereby an organosiloxane is produced in which silicon of the silanol is linked to silicon of the silicon halide by an oxygen atom, and separating the organosiloxane so produced from alkali metal halide produced by the reaction.

4. The method of preparing organosiloxane' materials which comprises reacting an alkali metal salt of an organo silanol, in which the organic radicals are monovalent hydrocarbon radicals free of. aliphatic unsaturation and are linked to the silicon by carbon to silicon bonds, with a silicon chloride in which any organic radicals present therein are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon by carbon to silicon bonds in the absence of moisture, in such proportions that the atomic ratio of chlorine to alkali metal is at least 1, and separating organosiloxane so produced from alkali metal chloride produced by the reaction.

5. The method of preparing organosiloxane materials which comprises reacting an alkali metal salt of an organo silanol, in which the organic radicals are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon by carbon to silicon bonds, with a silicon halide in which any organic radicals present therein are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon by carbon to silicon bonds in such proportions that the atomic ratio of halogen to alkali metal is at least 1. and separating organoarson-11o 1:9 siloxane so produced from alkali metal halide produced by the. reaction.

6. The method of preparing organosiloxane materials which comprises reacting an alkali metal salt of a monoorgano silanol in which the organic radicals are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon by carbon to silicon bonds, with a silicon halide in which anyorganic radicals present. therein are monovalent hydrocarbon radicals free of aliphatic unsaturat-ion and are linked to the silicon by carbon to silicon bonds, whereby a siloxane is produced in which the siliconofthe silanol is linked to the silicon of the silicon halide through an oxygen atom.

7. The method of preparing organosiloxane materials which comprises reacting an alkali metal salt. of a diorgano. silanol in whichthe organic radicals are monovalent hydrocarbon radicals. iree of aliphatic unsaturation and are linked to. the silicon by carbon to silicon bonds, with a. silicon halide in. which any organic radicals present therein are. monovalent hydrocarbon radicals free, of aliphatic unsaturation and are. linked to the silicon by carbon. to silicon bonds, whereby a siloxane is. produced, in whichv the silicon of the silanol is linked to the silicon of the silicon halide through an oxy en atom.

8.. The method of preparing organosiloxane 20 materials which comprises reacting an alkali metal salt of a triorgano silanol in which the organic radicals are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the silicon by carbon to silicon bonds, with a silicon halide in which any organic radicals present therein are monovalent hydrocarbon radicals free of aliphatic unsaturation and are linked to the. silicon by carbon to silicon bonds, whereby a siloxane is produced in which the silicon of. the silanol is linkedto the silicon of the silicon halide through an oxygen atom.

J-AMES FRANKLIN HYDE.

REFERENCES, CITED- The following references are of record. in the file of this patent:

UNITED STATES PATENTS.

Number Name Date 2,438,055. Hyde Mar. 16, 1948 2,443,353 Hyde June 15-, 1948 2;.4:5:3,092 Hyde Nov. 2, 19. 8

OTHER. REFERENCES Volnov et. aL: Jour... Gen. Chem.. U. S. S. R., vol. l0 (1940-), pages; 1600-1604..

Sommer et al.: Jour. Amer. Chem. Soc., vol. 68; (19%.), pagesv 4%"487 

1. THE METHOD OF PREPARING ORGANOLILOXANE MATERIALS WHICH COMPRISES REACTING AN ALKALI METAL SALT OF AN ORGANO SILANOL, IN WHICH THE ORGANIC RADICALS ARE MONOVALENT HYDROCARBON RADICALS FREE OF ALIPHATIC UNSATURATION AND ARE LINKED TO THE SILICON BY CARBON TO SILICON BONDS, WITH A SILICON HALIDE IN WHICH ANY ORGANIC RADICALS PRESENT THEREIN ARE MONOVALENT HYDROCARBON RADICALS FREE OF ALIPHATIC UNSATURATION AND ARE LINKED TO THE SILICON BY CARBON TO SILICON BONDS, WHEREBY A SILOXANE IS PRODUCED IN WHICH THE SILICON OF THE SILANOL IS LINKED TO THE SILICON OF THE SILICON HALIDE THROUGH AN OXYGEN ATOM. 